System and method for rotary drive curved track in a conveyor system

ABSTRACT

A system and method for a rotary drive for a curved track section of a conveyor. The system includes: a rotary motor; a wheel provided to the curved track section and driven by the rotary motor, the wheel includes an engagement mechanism configured to engage with a moving element; and a control system configured to control the wheel/rotary motor, such that the engagement mechanism engages a moving element adjacent a beginning of the curved track section and controls the moving element through the curved track section and releases the moving element adjacent an end of the curved track section. The method includes: moving a moving element toward the curved track section; controlling at least one of the moving element and a wheel such that the moving element and the wheel engage; controlling the moving element on the curved track section; and releasing the moving element.

FIELD

The present disclosure relates generally to a system and method for arotary drive curved track in a conveyor system and, more particularly,to a system and a method for driving a moving element around a curvedtrack section in a conveyor system.

BACKGROUND

In conventional conveyor systems, a moving element is controlled to movealong a track, typically via bearings that are provided on the movingelement or on the track and may include rails or the like for guidingthe moving element. In order to make a conveyor system easier toconstruct, the track is often formed in sections/modules and thesections are then attached together to form a longer track.

Conventional conveyor systems may be constrained where there arecurvilinear or curved sections of track for various reasons. Forexample, as the radius of the curved section is generally smallertowards the interior of the curve than the exterior of the curve,conventional linear motor systems and, in particular, linear motorconveyor systems, may encounter problems with the arrangement andconfiguration of moving elements as they travel through curved sectionsbecause of the differing levels of support provided to the movingelement when on a curved section of track.

Further, with regard to linear motor systems, conventional linear motorsystems with curvilinear or curved sections of track may produceunwanted forces on a moving element traversing a curved track section.For example, the unwanted forces may be caused by undesirable rates ofchange of acceleration, often called “jerk”, as the moving element movesthrough the curve. This “jerk” can lead to instability of the movingelement and any objects on the moving element, such as a workpiece, afixture, or the like.

Conventional linear motor systems may also have difficulty trackingmoving elements when the moving elements traverse a curvilinear orcurved section of track and/or during transition from curvilinear orcurved sections to straight sections of track.

As such, there is a need for an improved system and method for handlingcurvilinear or curved sections of a conveyor track.

SUMMARY

According to one aspect herein, there is provided a system for a rotarydrive for a curved track section of a conveyor, the system including: arotary motor; a star wheel provided to the curved track section anddriven by the rotary motor, wherein the star wheel may include anengagement mechanism configured to engage with a moving element on theconveyor; a control system configured to control the star wheel, via therotary motor, such that the engagement mechanism engages a movingelement adjacent a beginning of the curved track section and controlsthe moving element through the curved track section and releases themoving element adjacent an end of the curved track section.

In some cases, the star wheel may include at least one spoke, and thespoke may include a spoke engagement mechanism configured to engage witha moving element of the conveyor system. In some cases, the spokeengagement mechanism may include a bias portion, wherein the biasportion is configured to assist the engagement mechanism to engage withthe moving element. In some cases, the spoke engagement mechanism mayfurther include a bearing configured to engage with a moving elementengagement mechanism provided to the moving element. In this case, themoving element engagement mechanism may include a recess for acceptingthe bearing.

In some cases, the engagement mechanism may include or may additionallyinclude a moving element engagement mechanism. In one example, themoving element engagement mechanism may include a friction pad biasedtoward the star wheel and a friction surface on the star wheelconfigured to engage the friction pad.

In some cases, the system may further include a magnetic elementprovided to the curved track section and to the moving element tomagnetically attract the moving element toward the curved track section.

In some cases, the curved track section may include an electromagneticdrive for driving the moving element and the control system may beconfigured to control the rotary drive and electromagnetic drive tooperate such that the star wheel and an engaged moving element move atthe same speed.

In some cases, the system may further include one or more guide railsprovided to the curved track section wherein the one or more guide railsare aligned with one or more guide rails on an adjacent section of theconveyor.

In some cases, the star wheel may be provided at a bottom of the curvedtrack section.

In some cases, the rotary drive may be a servo drive.

According to another aspect herein, there is provided a method for arotary drive for a curved track section of a conveyor, the methodincludes: moving a moving element on a first straight track section ofthe conveyor toward the curved track section; controlling the movingelement and a star wheel driven by the rotary drive such that the movingelement and the star wheel engage adjacent to the curved track section;controlling the moving element on the curved track section via the starwheel; and releasing the moving element from the star wheel onto asecond straight track section of the conveyor by releasing theengagement.

In some cases, the first and second straight track sections may be thesame straight track section.

In some cases, the moving element and the star wheel may engage in asynchronized manner.

In some cases, the moving element and the star wheel may engage via alocking mechanism.

Other aspects and features of the present disclosure will becomeapparent to those ordinarily skilled in the art upon review of thefollowing description of specific embodiments in conjunction with theaccompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the attached Figures.

FIG. 1 shows a schematic drawing of an embodiment of a conveyor systemthat includes a track, made up of track section, and moving elements;

FIG. 2 shows a perspective view of an embodiment of a conveyor systemthat includes a track, made up of track section, and moving elements;

FIG. 3 shows a view of an embodiment of a track section having twomoving elements on it;

FIG. 4 illustrates an embodiment of a system for a motor driven curvedtrack section on a conveyor system;

FIG. 5 illustrates another example embodiment of a system for a motordriven curved track section;

FIG. 6 shows the interaction between the star wheel and moving element;

FIG. 7 shows the transition from a curved track section to a straighttrack section using the system;

FIG. 8 illustrates an embodiment of an engagement mechanism between thestar wheel and the moving element involving a biasing member;

FIG. 9 illustrates another embodiment of an engagement mechanism betweenthe star wheel and the moving element involving a gear-like connection;and

FIG. 10 illustrates another embodiment of an engagement mechanismbetween the star wheel and the moving element involving a frictionconnection.

DETAILED DESCRIPTION

Generally, the present disclosure provides for an improved system andmethod of handling curved sections of a conveyor, in particular, byusing a rotary motor driven curved track section. The curved tracksection may be part of a conveyor that also includes straight tracksections. The straight track sections may be driven by anelectromagnetic motor drive, servo motor drive or the like. As movingelements travel along the conveyor, there are generally one or morestraight sections followed by a curved track section. The curved tracksection may be a turn through any number of degrees but are typically45, 90, 135 or 180 degrees or the like. In some cases, the curved tracksection may be a transition between differently driven straight tracksections, or may itself be driven via different types of motor drives.The present disclosure provides for a rotary driven curved track sectionbetween straight sections, which may include additional support for themoving element during the curved transition. This additional support isintended to provide for a smoother transition between straight sections,via the curved section, and provide for an agnostic solution as themoving element may transition between differently driven conveyor tracksections (curved or straight).

Conventional conveyor systems tend to be constructed through acombination of straight and curved track sections. Conventionally, asingle drive system may be used to drive all sections in a givenconveyor system. Generally, an electromagnetic drive tends to be costlyand the kinematics of a curved section for an electromagnetic drive mayrequire a larger minimum radius than for a differently driven curvedsection, which may impact the overall footprint of the conveyor system.

As users of conveyor systems may want to include sections of track thatare driven via different motor drives, or may want to include curvedsections with a smaller radius than may be offered in a conventionalsystem, a curved track system and method may be preferred. In the systemand method provided herein, the curved track section may include arotary driven star wheel having radial spokes for engaging a movingelement. In some cases, the spokes may include a biasing member forproviding engagement between the spoke and the moving element, althoughit should be noted that the biasing member is not required for allembodiments.

In the following description, the examples relate to a linear motorconveyor system (for the straight sections) but the same or similarsystem and method can generally be used with other conveyor systems orhybrid conveyor systems that require a curved track section.

FIG. 1 shows a schematic diagram of an example conveyor system 20. Theconveyor system 20 includes one or more track sections 25, 26 defining atrack. In FIG. 1 , a plurality of straight track sections 25 areprovided with two curved sections 26. A plurality of moving elements 35are provided to the track and move around on the conveyor system 20. Ina manufacturing environment, the moving elements 35 are intended totravel between workstations (not shown) and may support a pallet orproduct (not shown) that is to be operated on automatically by, forexample, a robot, while moving or at a workstation or may travel to aworkstation or other work area intended for manual operations. Throughthe operation of the conveyor system 20, various operations areperformed to provide for the assembly of a product. In this disclosure,the terms “moving element” and “pallet” may sometimes be usedinterchangeably, depending on the context.

FIG. 2 illustrates a perspective view of another example linear motorconveyor system 100 having one or more track sections 102, 103 defininga track 106, and one or more moving elements 104 which are configured toride, move or travel along the track 106. In FIG. 2 , there are fourstraight track sections 102, and two corner track sections 103, and aplurality of moving elements 104. However, it will be understood thatthe modular nature of the track sections allow for various sizes andshapes of conveyors and any appropriate number of moving elements. InFIGS. 1 and 2 , the corner (or curved) track sections 103 are 180 degreeturns but in some configurations the curved track sections 103 may havedifferent angles such as 45, 90, 135 degree angles or the like. Some ofthe principles of operation of a similar track section are described inmore detail in, for example, U.S. Pat. No. 8,397,896 to Kleinikkink etal., which is hereby incorporated herein by reference.

As noted, the conveyor system 100 may include a plurality of tracksections 102, 103, which are mechanically self-contained and separablefrom one another so as to be modular in nature. In order to be modular,each track section 102, 103 may house electronic circuitry and/ormechanical parts for powering and controlling the related track section102, 103 and/or there may be a controller/control system 107 thatcontrols the related track section or the track 106 overall (only onecontroller is shown but other controllers for track sections may beincluded as well). In some cases the track controller may communicate orinterface with track section controllers provided for each of the tracksections 102, 103. The controller(s) may include a processor thatexecutes a program stored on a machine readable medium. The machinereadable medium may be a part of the controller or at a remote locationor the like.

In a linear motor conveyor system 100, the track 106 may produce amagnetic force for moving the moving element 104 along the track 106.The magnetic force can also capture, support or hold the moving element104 on the track 106. The magnetic force is at least partly generated bythe interaction of the magnetic flux created by embedded coils of thetrack 106 and magnetic elements of the moving element 104. It will beunderstood that conveyor systems with different motor drives may bedriven in other manners.

FIG. 3 illustrates an embodiment of a linear motor conveyor system 100that includes a straight track section 102 and two moving elements 104.The track 102 may be made up of track sections 102, joined end-to-end,with one or more guide rails 108 of each track section 102 aligned witha guide rail 108 of adjacent track sections 102. In this embodiment, thetrack section 102 includes a guide rail 108 located in an upper portionof track section 102, and the guide rail 108 has dual shaped grooves110, a lower guide rail 108 is flat. The moving elements 104 includebearings 112 that are correspondingly shaped in order to run along acorresponding guide rail 108, each bearing 112 running inside arespective shaped groove 110. The bearings 112 may be offset and suchthat for a moving element 104 having two shaped bearings 112, eachshaped bearing may run inside a separate respective shaped groove 110.

In some embodiments, the track section 102 may produce a magnetic forcefor moving the moving element 104 along the track 102. The magneticforce can also capture/hold the moving element 104 on the track 102. Insome cases, the magnetic force is created by the interaction of themagnetic flux created by coils (not shown) embedded in/under the tracksection and magnetic elements (not shown) of the moving element 104. Themagnetic force can be thought of as having a motive force component fordirecting movement of the moving element 104 along a direction of travelon the track 102, and a capturing force component to laterally hold themoving element 104 on the track 102 and in spaced relation to the tracksurface. In at least some conveyor systems, the motive force and thecapturing force can be provided by the same magnetic flux.

Generally speaking, the track sections 102, 103 will be mounted on asupport structure (not shown) so as to align and abut one another inorder to form the track 106. As noted above, each track section may becontrolled by a control system or by a track control system 107 thatcontrols a plurality of or all of the track sections.

In embodiments herein, reference numbers of elements may refer to thoseof the conveyor illustrated in FIGS. 2 and 3 , however, this is forreference to similar elements only and elements of each embodiment maybe used with other embodiments as would be appropriate for theapplication desired.

Where there are curvilinear or curved track sections in a linear motorconveyor system, conventional linear motor systems may be constraineddue to the nature of the linear motor used. As the radius of the curvedsection is generally smaller towards the interior of the curve than theexterior of the curve, conventional linear motor conveyor systems canencounter problems due to the positioning of coils for the motor. Inorder to overcome this difference in radius, some conventional linearmotor conveyor systems may have coils that fan out towards the exteriorof the curve, which may cause inconsistencies in magnetic flux. Otherconventional systems may have each loop of the coil in the curvedsection at a different angle than the loops adjacent to it; which may bedifficult to construct and may require complex control systems to drivethe coils. As well, with coils that fan out or at different angles,there may be difficulty in constructing and operating interleaved coils.

Conventional linear motor conveyor systems with curvilinear or curvedtrack sections may also produce unwanted forces on a moving elementtraversing the curved track section. The excessive forces may be causedby undesirable rates of change of acceleration, hereinafter called“jerk”. Jerk can have unwanted consequences such as shifting componentsbeing carried by the moving element or the like. Jerk may be especiallypronounced at the transition point between the curved section of trackand a straight section of track. As such, some conventional conveyorsystems may limit the speed of the moving elements as they travelthrough the curved track section to minimize jerk. However, limitingspeed may constrain the overall conveyor system throughput.

Conventional linear motor conveyor systems also may have somebearings/wheels of a moving element experience different forces orrotate at a different speed than other bearings/wheels of the movingelement when on a curve. This effect may be especially pronounced wherethe moving element travels on a top surface of a track. This effect mayproduce undesirable wear on the bearings/wheels and require that thebearings/wheels be made out of expensive material to resist wear, orrequire that expensive and complex differential systems be implementedon the moving element. Some linear motor conveyor systems may alsorequire a contact surface for support or guidance around a curve. Such acontact surface may require a mechanism to engage/disengage with movingelements (or, in some cases may even be present on the full conveyor)which can introduce friction and thereby become a wear element that maygenerate debris. In embodiments herein, the moving elements can beconfigured to travel around the curve without requiring any additionalcontact support (for example if attracted/supported on the track by amagnetic force).

Embodiments of the system for a rotary motor curved track sectiondetailed herein are intended to be used along with a conveyor havingcurved and straight track sections and, in particular, straight tracksections that are driven by a linear motor. However, different drivesystems may also be used for the straight track sections. The system isintended to include a rotary driven motor and a star wheel. In somecases, the rotary motor may be a servo-motor or the like. As the movingelement moves from a straight section, driven by, for example, a linearmotor, to a curved section, the moving element is configured to engagewith the star wheel via, for example a spoke. The star wheel rotates,thereby moving the shuttle along the circumference of the curved tracksection. In some cases, for a linear motor driven conveyor system, themagnetic force from the moving element can still be used to hold themoving element against the track, acting against the centripetal forceand acceleration around the curve.

FIG. 4 illustrates an embodiment of a system for a rotary drive curvedtrack 200 when applied to a curved track section 202 a of a conveyor. Inthis example, a conveyor includes a transition from a straight tracksection 202 b to the curved track section 202 a to a further straighttrack section 202 b. The system 200 includes a rotary drive 204 fordriving a star wheel 206. The rotary drive 204 and star wheel 206 areconfigured to work with the curved track section 202 a. The star wheel206 is configured to engage a moving element 104 as the moving element104 transitions onto the curved section 202 a. In this embodiment, thestar wheel 206 includes a plurality of radial spokes 208 and the starwheel 206 may engage each moving element 104 via a related radial spoke208. Each spoke 208 may include a spoke engagement mechanism (not shownin FIG. 4 but described below) which is intended to provide engagementwith the moving element as it enters and traverses the curved tracksection 202 a.

FIG. 5 illustrates an alternative embodiment of a system for a rotarydrive curved track 300 as applied to a curved track section 302. Thesystem 300 is similar to the system 200 shown in FIG. 4 , but is locatedon the top of the curved track section 302 as opposed to the bottom ofthe curved track section 202 a. Similar to FIG. 4 , the curved tracksection 302 may be operatively connected with straight conveyor tracksections that may use various drive types, for example, anelectromagnetic linear motor drive, a servo-motor drive or the like. Thesystem 300 includes a star wheel 306 driven by a rotary drive (notshown). The star wheel 306 includes at least one spoke 308 projectingradially from an external perimeter of the star wheel 306 and extendinga predetermined amount outside of the perimeter of a rail of the curvedtrack section 302. The number and shape of spokes per star wheel maydepend on the radius of the star wheel, radius of the curved tracksection, the setup of the moving elements on the conveyor system, speedof movement of the star wheel, and the like. Generally speaking, thenumber/spacing of spokes and radial distance between spokes is limitedby the minimum pitch of the moving elements. It is possible to addspokes to this limit depending on the application.

In this arrangement of the star wheel, the curve can be more compactbecause the curve does not require a drum/hub to both support andtransport the moving elements around a corner. The star wheel can bemounted above or below the track.

In this embodiment, each spoke 308 is configured to be received by amoving element engagement mechanism, such as, for example, recess 310 ofthe moving element 104. In some cases, the moving element may beretrofitted with an addition 312 including the recess 310, which isintended to allow currently used moving elements to continue to be usedon a conveyor system having the system 300 for the curved track section.In other cases, the moving element may be designed as a single unit withan engagement mechanism such as the recess corresponding to a shape of aspoke on the star wheel. At a connecting end of each spoke 308, themoving element engagement mechanism may include a bearing 314 or ballcorrespondingly shaped to the recess 310. Although the recess 310 isshown as a curved recess in this figure, it will be understood thatother shapes of recesses may be used, and the spoke may include acorrespondingly shaped bearing or the like.

In some cases, the bearing of the spoke may be made of a material withslight give, flexibility, or the like, to ensure the bearing may stilloperatively engage the recess even if the recess includes slightmanufacturing tolerances or misalignments.

FIG. 6 illustrates the engagement of the moving element 104 on a spoke208 of the star wheel 206 for the system shown in FIG. 4 . FIG. 7 is abottom view illustrating the transition from a straight track section202 b to the system 200.

As illustrated in FIG. 7 , the moving element 104 travels along thestraight track section and is controlled by the controller to adjust itsposition, speed and the like. As noted above, the straight track sectionmay be driven by an electromagnetic linear motor drive, a servo-motordrive or the like. On reaching the curved track section 202 a, themoving element 104 is controlled by the controller to match its approachsuch that the controller can control the rotary motor to drive the starwheel 206 such that the spoke 208 of the star wheel 206 engages themoving element 104. Generally speaking, the controller 107 controls boththe straight track section and the rotary motor to have the spoke 208engage with the moving element 104. However, in some cases, one of thestraight section or rotary motor may be moving at a predetermined speedor having a predetermined speed profile while the other of the straightsection or rotary motor may be adjusted by the controller to cause theengagement.

In this embodiment, the spoke 208 engages the moving element 104 via amoving element engagement mechanism provided to the moving element 104(such as a recess formed in the moving element or in an additionattached to the moving element 104). The rotary drive motor rotates thestar wheel 206 and spoke 208 around the curved track section 202 a asillustrated in FIG. 6 . The use of an engagement mechanism such as thespoke 208 and recess 210 allows for the mechanical control of the movingelement 104 as it moves around the curved track section 202 a. In thisembodiment, the moving element 104 can also be held against the curvedtrack section 202 a via a magnetic attraction between the moving element(for example, a magnet in the moving element) and the curved tracksection 202 a (for example, a steel structure or the like in the curvedtrack section). However, in other embodiments, the spoke and engagementmechanism on the moving element may be configured to provide additionalmechanical support or locking of the moving element so that control ismaintained. In any event, the engagement between the spoke and themoving element is configured to allow the controller to maintaininformation about the location of the moving element and control of themoving element's movement.

Following rotation around the curved track section 202 a by the system200, the moving element 104 is moved/transitioned onto a second straighttrack section 202 b. The second straight track section 202 b may bedriven by the same type of drive or a different type of drive systemthan the first straight track section. In this embodiment, the starwheel 206 transitions the moving element 104 to the second straightsection 202 b via an opposite process of that illustrated in FIG. 7 ,wherein the spoke 208 moves the moving element onto the straight tracksection 202 b and disengages from the engagement mechanism (recess 310)of the moving element 104. The controller then controls the straighttrack section 202 b to move the moving element 104 further down theconveyor.

The system shown in FIG. 5 would operate in a similar manner but starwheel and spoke(s) would be at the top of the curved track section.

In some embodiments, the star wheel/rotary drive may be configured toallow for queueing or stopping/holding moving elements on the curvedtrack section. For example, queuing/buffering may include the ability toslow down and speed up as well as stopping for a predetermined timeperiod and starting as needed. In some embodiments herein, control ofthe star wheel (and thus movement of the moving elements on the curvedtrack section) can be controlled independently of but in co-ordinationwith the straight track sections (and thus movement of the movingelements on the straight track sections) even in high throughputapplications. For stopping/holding, this can occur, for example, when amoving element is stopped to perform some operation/task on the curvedtrack section. Because of the flexibility of control, thistask/operation could be something that occurs every cycle or somethingthat occurs occasionally such as removing a rejected part or performingan audit. Further, the amount of time of the stop or hold can also beprogrammable. Still further, the stopping/holding location can beprogrammable because the star wheel can be programmed to stop or hold atany position along the curved track section.

In some embodiments, the star wheel and rotary drive can be controlledto move the moving element onto the curved track section and thenreversed to return the moving element to the same track section. Thismay be useful in, for example, situations where one or more movingelements are to be queued at a point in the manufacturing cycle and thenreturned.

In some cases, even if the curved track section includes a magneticmotor providing electromagnetic forces to hold and/or move the movingelement, the star wheel and spoke may be provided in order to provideadditional support/control for moving the moving element around thecurved track section. In these cases, the star wheel may be driven ornot-driven depending on the application.

In general, the system herein is intended to be agnostic with respect tothe drive system of the conveyor system. In some cases, the straighttrack sections and the curved track section may all have different drivetypes, or the straight track sections may be of the same drive type, orthere may be multiple drive types in any given track section.

FIG. 8 illustrates an embodiment of a spoke 408 that may be used as aspoke for embodiments of the system. While a particular spokearrangement is described herein, it is intended to be indicative of theprinciples involved and other formats/embodiments of an engagementmechanism may use similar or different principles and achieve the sameor similar results. In this embodiment, each spoke 408 includes a spokeengagement mechanism 410 for engaging with the moving element 104. Inthis case, the spoke engagement mechanism 410 includes a biasing member418 to provide bias to the spoke as it engages with and disengages fromthe moving element 104. The biasing member 418 may be a spring or likeconstruction designed to allow the spoke to flex in one or moredirections in the event the spoke does not directly engage the movingelement. In some embodiments, a separate biasing member may not beneeded. The spoke engagement mechanism 410 may further include a bearing420 or other form of connector at an end of the spoke and coupled withthe biasing member. The moving element 104 receives thisconnector/bearing 420, via a moving element engagement mechanism 430,for example a recess 432, in order to provide support and movement ofthe moving element around the curved track section via the star wheel.In some cases, the recess 432 may have a slightly chamfered entrance toallow for some level of misalignment or machining tolerances or the likewith the bearing 420 during engagement. Although a generallycircular/semi-circular connector/bearing and recess are shown, it willbe understood that these are intended to be cooperatively shapedcomponents, and may be shaped or formed in other manners. In some cases,the spoke engagement mechanism 410 and the moving element engagementmechanism 430 may together be referred to as an “engagement mechanism”.

FIG. 9 illustrates another embodiment of an engagement mechanism 500between the star wheel and the moving element. In this case, the starwheel includes a spoke 503. In this case, the spoke 503 includes a spokeengagement mechanism 505, which is an elongated head 505, that extendsbeyond the boundary of the star wheel. In some cases, the elongated head505 may have a predetermined level of flexibility to provide bias to theelongated head as it engages with and disengages from the moving element104. The moving element 104 receives this elongated head 505, via amoving element engagement mechanism 508, for example a recess 510. Insome cases, the recess 510 may have a wider entrance to allow for somelevel of misalignment or machining tolerances or the like with theelongated head 505 during engagement. In this embodiment, the engagementmechanism is somewhat like a gear tooth engaging with a correspondingrecess.

In FIGS. 8 and 9 , the engagement mechanism represents an example of asynchronized engagement option. In these examples, the spoke or starwheel engagement mechanism is generally timed to be synchronized withthe moving element engagement mechanism. A synchronized engagement canassist if there are higher forces involved, such as can be the case withfast moving conveyors.

FIG. 10 illustrates another embodiment of an engagement mechanism 600between the star wheel and the moving element. In this case, the starwheel includes a star wheel engagement mechanism that is, for example, afriction surface 605. The moving element 104 includes a moving elementengagement mechanism 610 that includes a friction pad 615 and a biasingmechanism 620, in this case a spring 620, which biases the friction pad615 against the friction surface 605. In this example, the engagementmechanism 600 does not need to be synchronized as the moving element canengage with the star wheel as it enters the curved track section. Inthis case, the star wheel generally may not need to be controlled asprecisely as the synchronized engagement mechanisms.

Interestingly, in some embodiments, in a situation where the movingelement does not engage correctly with the spoke as intended, the spokeor a following spoke (or following moving element) may continue tocontrol/move the moving element around the curved track section suchthat the moving element can be “recovered” when it is moved from thecurved track section back to a straight track section.

Embodiments of the system are intended to allow for a smaller size ofcurved track section as the rotary drive and star wheel can generallyfit in a smaller area than what would conventionally be required for amagnetic motor drive in a curved track section or for alternate types ofdrives/curves. Further, the spokes of the star wheel can be configuredsuch that they do not extend beyond the outside of the moving elementssuch that additional space is not needed to control/move the movingelements around the curved track section. Having the spokes at thebottom of the curved track section is intended to also reduce risk ofthe spokes interfering with other operations, operators or the like.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments. However, it will be apparent to one skilled in the artthat these specific details may not be required. In other instances,well-known structures may be shown in block diagram form in order not toobscure the understanding. Further, it will be understood that variouselements/aspects of each embodiment described herein may be used withother embodiments as appropriate and that each embodiment may include asub-set of the elements/aspects described therewith.

Embodiments of the disclosure can be represented as a computer programproduct stored in a machine-readable medium (also referred to as acomputer-readable medium, a processor-readable medium, or a computerusable medium having a computer-readable program code embodied therein).The machine-readable medium can be any suitable tangible, non-transitorymedium, including magnetic, optical, or electrical storage mediumincluding a diskette, compact disk read only memory (CD-ROM), memorydevice (volatile or non-volatile), or similar storage mechanism. Themachine-readable medium can contain various sets of instructions, codesequences, configuration information, or other data, which, whenexecuted, cause a processor/controller to perform steps in a methodaccording to an embodiment of the disclosure. Those of ordinary skill inthe art will appreciate that other instructions and operations necessaryto implement the described implementations can also be stored on themachine-readable medium. The instructions stored on the machine-readablemedium can be executed by a processor or other suitable processingdevice, and can interface with circuitry to perform the described tasks.

Applicants reserve the right to pursue any embodiments orsub-embodiments or combinations thereof disclosed in this application;to claim any part, portion, element and/or combination thereof,including the right to disclaim any part, portion, element and/orcombination thereof.

The above-described embodiments are intended to be examples only.Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art without departingfrom the scope, which is defined solely by the claims appended hereto.

What is claimed is:
 1. A rotary drive system for a curved track sectionof a conveyor, wherein the conveyor includes at least one straight tracksection that feeds into or out of the curved track section, the systemcomprising: a rotary motor; a star wheel provided to the curved tracksection and driven by the rotary motor, wherein the star wheel comprisesat least one spoke configured to engage with a recess provided on amoving element on the conveyor, wherein the at least one spokecomprises, at a distal end thereof, a biasing member configured to allowthe at least one spoke to flex in one or more directions and at leastone bearing coupled with the biasing member: a control system configuredto control the star wheel, via the rotary motor, such that the at leastone spoke engages the moving element adjacent a beginning of the curvedtrack section and controls the moving element through the curved tracksection and releases the moving element adjacent an end of the curvedtrack section.
 2. A system according to claim 1 wherein the engagementmechanism comprises a moving element engagement mechanism comprising afriction pad biased toward the star wheel and a friction surface on thestar wheel configured to engage the friction pad.
 3. A system accordingto claim 1 further comprising a magnetic element provided to the curvedtrack section and to the moving element to attract the moving elementtoward the curved track section with sufficient magnetic force tosupport the moving element while also allowing the rotary drive to movethe moving element.
 4. A system according to claim 1 wherein the curvedtrack section comprises an electromagnetic drive for driving the movingelement and the control system is configured to control the rotary driveand electromagnetic drive to operate such that the at least one spokeand an engaged moving element move at the same speed.
 5. A systemaccording to claim 1 further comprising one or more guide rails providedto the curved track section wherein the one or more guide rails arealigned with one or more guide rails on an adjacent section of theconveyor.
 6. A system according to claim 1 wherein the star wheel isprovided at a bottom of the curved track section.
 7. A system accordingto claim 1 wherein the rotary drive is a servo drive.
 8. A method forcontrolling a curved track section of a conveyor, the method comprising:moving a moving element on a first linear motor drive straight tracksection of the conveyor toward the curved track section via the linearmotor drive: controlling at least one of the linear motor drive and arotary drive of a star wheel such that a recess provided to the movingelement and a spoke of the star wheel engage adjacent to the curvedtrack section, wherein the spoke comprises a biasing member and abearing, at a distal end thereof; controlling the moving element on thecurved track section via the rotary drive of the star wheel; releasingthe moving element from the spoke of the star wheel onto a second linearmotor drive straight track section of the conveyor by continued rotationof the star wheel.
 9. A method according to claim 8 wherein the firstand second straight track sections are the same straight track section.10. A method according to claim 8 wherein the moving element and thestar wheel engage in a synchronized manner.
 11. A method according toclaim 8 wherein the recess on the moving element and the spoke on thestar wheel are held together by a locking mechanism.